Oil desulfurization method and system

ABSTRACT

An oil desulfurization method may be used to desulfurize various oils, such as used motor oil, crude oil, diesel, high sulfur fuel oil, mid sulfur fuel oil, off-spec fuel oil, and off-spec diesel, to produce a finished product of lower sulfur oil and a high sulfur fuel oil or sulfur containing oil product. Preferably, the method may include the steps of: mixing an oxidizing material with sulfur containing oil to produce a first mixture; subjecting the first mixture to at least one of heat and pressure to oxidize the sulfur in the first mixture; mixing at least one solvent with the first mixture to produce a second mixture; and separating the second mixture to produce a low sulfur oil product and a third mixture, the third mixture having a high sulfur oxidized oil and the at least one solvent.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of the filing date of U.S. Provisional Application No. 63/075,357, filed on Sep. 8, 2020, entitled “OIL DESULFURIZATION METHOD AND SYSTEM”, which is hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

This patent specification relates to the field of fluid desulfurization. More specifically, this patent specification relates to a method and system for the desulfurization of oil.

BACKGROUND

Refining of crude oil and used oil to final products requires desulfurization of the oil. Regulations that govern transportation fuels have become increasingly stringent with respect to sulfur content. Many petrochemical products are likewise produced to be almost sulfur-free. The removal of sulfur from oil is consequently one of the central conversion requirements in most refineries and the price (and processing cost) of crude oil and used oil is influenced by its sulfur content.

Therefore, a need exists for novel methods and system for the desulfurization of crude oil, fuel oils, and used oil. A further need exists for novel oil desulfurization methods and systems that are economical and efficient.

BRIEF SUMMARY OF THE INVENTION

A desulfurization method and system are provided which may be used to desulfurize various oils, such as used motor oil, crude oil, diesel, high sulfur fuel oil, mid sulfur fuel oil, off-spec fuel oil, and off-spec diesel, to produce a finished product of lower sulfur oil and a high sulfur fuel oil or sulfur containing oil product.

In some embodiments, a desulfurization method may include the steps of: an oxidizing material with sulfur containing oil to produce a first mixture; subjecting the first mixture to heat and/or pressure to oxidize the sulfur in the first mixture, optionally in the presence of a catalyst; mixing one or more solvents with the first mixture to produce a second mixture; and separating the second mixture to produce a low sulfur oil product and a third mixture, in which the third mixture includes a high sulfur oxidized oil and the one or more solvents.

In further embodiments, the method may include the step of separating the one or more solvents from the third mixture to produce a high sulfur oxidized oil product.

In further embodiments, the method may include the step of passing the low sulfur oil product through a polar zeolite to extract additional oil holding sulfur. The polar zeolite may adsorb any oil holding sulfur and/or oxygen remaining in the processed low sulfur oil. Optionally, the zeolite extraction step may be used in place of and/or in addition to the polar solvent extraction step.

In some embodiments, a desulfurization system may include a pump which may receive oil from one or more oil sources. One or more gas and/or liquid oxidizing material sources may provide oxidizing materials to the oil which may then be mixed via a materials oil mixer and then communicated to one or more cavitation reactors, optionally in the presence of a catalyst. A solvent source may provide one or more solvents, and preferably at least one polar solvent, to the oil mixture which may then be mixed via a solvent oil mixer. After exiting the solvent mixer, the oil mixture may be communicated to a centrifuge, or other type of separation device, that may separate the oil mixture into a solvent and sulfur containing oil mixture and a low sulfur oil that substantially does not contain sulfur and attached oxygen. The solvent and sulfur containing oil mixture may then be communicated to a solvent separator for separation of the solvent and oil containing sulfur. The separated solvent optionally may be reused in the oil desulfurization method. The sulfur containing oil separated from the polar solvent may be another product sold as a high sulfur fuel oil or sulfur containing oil.

In further embodiments, a desulfurization system may include a pump which may receive oil from one or more oil sources that have been heated and filtered via a heater and filter, respectively. One or more gas and/or liquid oxidizing material sources may provide oxidizing materials to the oil which may then be mixed via a materials oil mixer and then communicated to one or more cavitation reactors, optionally in the presence of a catalyst. A cooling device may reduce the temperature of the oil mixture that exits the cavitation reactors. A solvent source may provide one or more solvents, and preferably at least one polar solvent, to the oil mixture which may then be mixed via a solvent oil mixer. After exiting the solvent mixer, the oil mixture may be communicated to a centrifuge, or separation device that may separate the oil mixture into a solvent and sulfur containing oil mixture and a lower sulfur oil that substantially does not contain sulfur and attached oxygen. The solvent and sulfur containing oil mixture may then be communicated to a solvent separator for separation of the solvent(s) and oil containing sulfur. The separated solvent(s) may be reused in the oil desulfurization method. The sulfur containing oil separated from the polar solvent may be another product sold as a high sulfur fuel oil or sulfur containing oil.

BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiments of the present invention are illustrated as an example and are not limited by the figures of the accompanying drawings, in which like references may indicate similar elements and in which:

FIG. 1 depicts a block diagram of an example of an oil desulfurization system according to various embodiments described herein.

FIG. 2A illustrates a block diagram of a first part of another example of an oil desulfurization system according to various embodiments described herein.

FIG. 2B shows a block diagram of a second part of the example oil desulfurization system of FIG. 2A according to various embodiments described herein.

FIG. 3 depicts a block diagram of an example oil desulfurization method according to various embodiments described herein.

DETAILED DESCRIPTION OF THE INVENTION

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well as the singular forms, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one having ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

In describing the invention, it will be understood that a number of techniques and steps are disclosed. Each of these has individual benefit and each can also be used in conjunction with one or more, or in some cases all, of the other disclosed techniques. Accordingly, for the sake of clarity, this description will refrain from repeating every possible combination of the individual steps in an unnecessary fashion. Nevertheless, the specification and claims should be read with the understanding that such combinations are entirely within the scope of the invention and the claims.

For purposes of description herein, the terms “upper,” “lower,” “left,” “right,” “rear,” “front,” “side,” “vertical,” “horizontal,” and derivatives thereof shall relate to the invention as oriented in FIG. 1. However, one will understand that the invention may assume various alternative orientations and step sequences, except where expressly specified to the contrary. Therefore, the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.

Although the terms “first,” “second,” etc. are used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, the first element may be designated as the second element, and the second element may be likewise designated as the first element without departing from the scope of the invention.

As used in this application, the term “about” or “approximately” refers to a range of values within plus or minus 10% of the specified number. Additionally, as used in this application, the term “substantially” means that the actual value is within about 10% of the actual desired value, particularly within about 5% of the actual desired value and especially within about 1% of the actual desired value of any variable, element or limit set forth herein.

A new oil desulfurization method and system is discussed herein. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be evident, however, to one skilled in the art that the present invention may be practiced without these specific details.

The present disclosure is to be considered as an exemplification of the invention and is not intended to limit the invention to the specific embodiments illustrated by the figures or description below.

The present invention will now be described by example and through referencing the appended figures representing preferred and alternative embodiments. FIG. 1 illustrates a first example of an oil desulfurization system (“the system”) 100A, and FIGS. 2A and 2B illustrate a second example of an oil desulfurization system 100B according to various embodiments. It should be understood that the components and arrangement of components in the systems 100A, 100B, of FIGS. 1-2B are exemplary and non-limiting. The system 100A, 100B, may be used to desulfurize various sulfur containing oils, such as Used Motor Oil, Crude Oil, Diesel, High Sulfur Fuel Oil, Mid Sulfur Fuel Oil, Off-Spec Fuel Oil, and Off-Spec Diesel. In some embodiments, the system 100A, 100B, may comprise or may be in communication with one or more sulfur containing oil sources 11 that may include a used motor oil source 11A, a crude oil GT 30 API source 11B, a crude oil LT 30 API source 11C, a fuel oil or oil distillate source 11D, and/or any other source of oil that is desired to be desulfurized.

In preferred embodiments, the system 100A, 100B, may comprise one or more heaters 15 which may be used to increase the temperature of sulfur containing oil in or from a sulfur containing oil source 11 to decrease the viscosity of the sulfur containing oil to a desired level to improve flow and processing. A heater 15 may be configured to heat the sulfur containing oil to approximately 200 degrees Fahrenheit or to any other temperature or temperature range to achieve a desired viscosity of the oil. In some embodiments, a heater 15 may comprise a heat exchanger system. In some embodiments, a heater 15 may comprise an electric heating element. In still further embodiments, a heater 15 may comprise any suitable device or method for increasing the temperature of oil.

In some embodiments, a heater 15 may be in communication with a sulfur containing oil source 11. In further embodiments, oil exiting a sulfur containing oil source 11 may pass through a heater 15. In some embodiments, a heater 15 may be in communication with a filter 16. In still further embodiments, if sulfur containing oil from a sulfur containing oil source 11 already possess an appropriate viscosity the oil may bypass a heater 15 or heating stage.

In some embodiments, sulfur containing oil from an oil source 11 may be communicated to a filter 16 which may be used to remove suspended solids and other contaminates from the oil. In preferred embodiments, a filter 16 may comprise a screen-filter system and/or a horizontal centrifuge which may be configured to reduce solids. In further embodiments, a filter 16 may comprise any device or method which may be used to remove various solids and other contaminates from oil.

In some embodiments, the system 100A, 100B, may comprise one or more pumps 17 which may be used to motivate oil to, through, and/or from the components of the system 100A, 100B. A pump 17 may comprise a hydraulic pump, such as a gear pump, rotary vane pump, screw pump, bent axis pump, inline axial piston pumps and swashplate principle pumps, radial piston pumps, peristaltic pumps, or any other suitable type of pump which may be suitable for motivating oil to, through, and/or from the components of the system 100A, 100B. Preferably, a pump 17 may motivate sulfur containing oil into a materials oil mixer 21.

The system 100A, 100B, may utilize conduit 40 of any shape and size to provide fluid communication into, between, and from the components of the system 100. It should be understood that the suffixes of “A”, “B”, “C”, etc., designate different embodiments of conduit 40 so that the conduits 40A, 40B, 40C, etc., read on the teachings of conduit 40.

In preferred embodiments, conduit 40 may comprise or be formed from stainless steel. In other embodiments, conduit 40 may comprise or be formed from any type of pipe or conduit, such as Poly Vinyl Chloride (PVC) pipe and fittings, Chlorinated Poly Vinyl Chloride (CPVC) pipe and fittings, cross-linked polyethylene (PEX) pipe and fittings, galvanized pipe and fittings, black pipe and fittings, polyethylene pipe and fittings, copper pipe and fittings, brass pipe and fittings, vinyl pipe and fittings, or any other type of pipe or conduit suitable for communicating oil and solvents.

The system 100A, 100B, may mix one or more oxygen containing oxidizing materials, such as ambient air, ozone, compressed air, oxygen, nitrogen oxygen mixtures/compounds, liquids such as peracetic acid, hydrogen peroxide, and acetic acid, with the sulfur containing oil, via a materials oil mixer 21, to produce a first mixture comprising sulfur containing oil from one or more oil sources 11 and a volume of one or more gas and/or liquid oxidizing materials.

In some embodiments, the system 100A, 100B, may comprise a gas and/or liquid oxidizing materials source 19 that may be configured to provide one or more gas and/or liquid oxidizing materials into oil which may be then mixed in a materials oil mixer 21. A gas and/or liquid oxidizing materials source 19 may comprise any device or method for providing one or more gas and/or liquids which may be mixed with oil, such as a compressed gas or liquids tanks.

A materials oil mixer 21 may comprise any device or method for mixing oxidizing materials with oil, such as a static materials and oil mixer. Generally, a static mixer may comprise a precision engineered device for the continuous mixing of fluid materials, without moving components. In preferred embodiments, compressed gas and/or liquid oxidizing materials from an oxidizing materials source 19 may be introduced to the oil exiting a pump 17 with materials conduit 40H with the conduit 40G after the materials conduit 40H, 40G, juncture having a piping size enlarged to accommodate the added materials volume in the oil, and the materials and oil mixture may then pass through a static mixer type of materials oil mixer 21 to ensure proper oxidizing materials to liquid dispersion.

After the one or more a gas and/or liquid oxidizing materials are added to the sulfur containing oil to produce a first mixture, the first mixture may be subjected to heat (above ambient temperature) and/or pressure (above ambient pressure) to oxidize the sulfur in the first mixture. In preferred embodiments, the first mixture may be subjected to heat and/or pressure via a cavitation reactor 22, 22A, 22B. In some embodiments, the system 100B, may comprise two or more cavitation reactors, such as a first cavitation reactor 22A and a second cavitation reactor 22B, which may receive the materials and oil mixture and which may subject the materials and oil mixture to controlled cavitation. Optionally, a cavitation reactor 22, 22A, 22B, may subject the materials and oil mixture to controlled cavitation in the presence of a catalyst, and more preferably a zeolite catalyst, such as Zn-ZSM, Mo-ZSM, Fe-ZSM, or Co-ZSM so that the first mixture is subjected to oxidation of sulfur in the presence of a catalyst. In preferred embodiments, the system 100A, 100B, may comprise two or more cavitation reactors 22A, 22B, which may be operated in series, parallel, or any other combination. Optionally, the system 100A, 100B, may comprise one or more bypass conduits 40K, 40L, which may allow the oil and materials mixture to bypass one or more cavitation reactors 22A, 22B.

Preferably, the one or more cavitation reactors 22, 22A, 22B, may operate between approximately 10 to 80 psi, or approximately 2 to 40 psi inlet pressure and 5 to 30pounds per square in gauge (psig) back pressure. In other embodiments, the one or more cavitation reactors 22, 22A, 22B, may operate at any other suitable pressure so as to enable controlled cavitation of the materials and oil mixture is achieved in the cavitation reactors 22, 22A, 22B. Controlled cavitation of the materials and oil mixture achieved in the cavitation reactors 22, 22A, 22B, may provide oxidation of the sulfur in the oil of the first mixture by attaching oxygen to the sulfur in the oil molecules that contain sulfur. In some embodiments, the system 100A, 100B, may include a return conduit 40M which may be configured to return oil mixture that has exited cavitation reactor(s) 22A, 22B, to be returned to an oil source 11, such as a crude oil LT 30 API source 11C.

In some embodiments, the system 100A, 100B, may comprise one or more cooling devices 23 which may be used to cool the oxygen and oil mixture achieved in the cavitation reactors 22, 22A, 22B. As the cavitation process creates heating of the oil, a cooling device 23 may be used to cool the oil mixture after it exits a cavitation reactor 22, 22A, 22B. A cooling device 23 may comprise any device or method which may be used to reduce the temperature of the oil mixture. In preferred embodiments, a cooling device 23 may comprise a heat exchanger system. In further preferred embodiments, oil mixture may flow from the cavitation reactor(s) 22, 22A, 22B, into a heat exchanger system type of cooling device 23 that may be used to reduce the temperature of the oil mixture to near ambient.

In some embodiments, the system 100A, 100B, may comprise one or more solvent sources 24 which may provide one or more solvents, such as a polar solvent, into the oil mixture after it has exited the cooling device 23 from the cavitation reactor(s) 22, 22A, 22B, optionally via a solvent conduit 40Q, to produce a second mixture. A solvent source 24 may comprise any device or method for holding and dispensing a solvent, such as a polar solvent, into the oil mixture, such as a refrigerated or nonrefrigerated solvent tank. Preferably, a solvent source 24 may dispense one or more polar solvents into the first oil mixture, such as tamisolve, N-ethyl pyrrolidone (NEP), diethyl carbonate, ethylene carbonate dimethyl carbonate, cyrene, Dimethylformamide (DMF), N-Methyl-2-pyrrolidone (NMP), propylene carbonate, any other polar solvent, other types of solvents, or mixture(s) of solvents. In preferred embodiments, a polar solvent or mixture(s) of one or more solvents may be introduced into the oil mixture at a rate between approximately 10% to 100% of oil volume, depending on the type of oil being processed and the type of polar solvent. In further preferred embodiments, the polar solvent may be held in a refrigerated tank type of solvent source 24 and may be introduced to the oil stream between approximately 32 to 90 degrees Fahrenheit (although other temperatures may be used) to lower the viscosity of the solvent and increase the density. In further embodiments, a solvent source 24 may provide any other type of solvent.

In some embodiments, the system 100A, 100B, may comprise a solvent oil mixer 25 which may be configured to mix the oil and one or more solvents together to form a second mixture. A solvent oil mixer 25 may comprise any device or method for mixing one or more solvents and oil together. In preferred embodiments, a solvent oil mixer 25 may comprise a static mixer, and more preferably a gentle static mixer.

In some embodiments, the system 100A, 100B, may comprise a centrifuge 26, or any other suitable device, which may be configured to separate the solvent oil mixture (second mixture) to produce a low sulfur oil product and a third mixture having a high sulfur oxidized oil and polar solvent. A centrifuge 26 may comprise any type of centrifuge suitable for separating oil products by sulfur content. In some embodiments, a centrifuge 26 may comprise two or more centrifuges, such as a centrifuge bank. In preferred embodiments, a centrifuge 26 may comprise a disk stack centrifuge. The centrifuge 26 may generate a finished product of very low sulfur fuel oil (VLSFO) which may be placed into a finished product tank 27, and the centrifuge 26 may generate a third mixture comprising polar solvent with high sulfur oxidized oil. Optionally, the very low sulfur oil may be passed through a polar zeolite to remove more oil with sulfur with oxygen or without oxygen. The polar zeolite extraction may be used in place of and/or in addition to the polar solvent extraction.

In some embodiments, the system 100A, 100B, may comprise a solvent separator 28 which may be used for separation of the polar solvent and oil containing sulfur. A solvent separator 28 may comprise any suitable device or method for separation of the polar solvent and oil containing sulfur. In preferred embodiments, a solvent separator 28 may comprise a distillation system. Optionally, a distillation type solvent separator 28 may comprise a vacuum distillation system depending on the polar solvent used. In preferred embodiments, the distillation separated solvent can be reused in the extraction process and may be returned to the solvent source 24 via a solvent conduit 40U. The sulfur containing oil separated from the polar solvent may be a product sold as a high sulfur fuel oil (HSFO) or sulfur containing oil.

Referring now to FIG. 3, an oil desulfurization method (“the method”) 200 is provided. Optionally, one or more steps of the method 200 may be performed by an oil desulfurization system 100A, 100B, or the example components described above. In preferred embodiments, the method 200 may be used to desulfurize various oils, such as Used Motor Oil, Crude Oil, Diesel, High Sulfur Fuel Oil, Mid Sulfur Fuel Oil, Off-Spec Fuel Oil, and Off-Spec Diesel, to produce a finished product of lower sulfur oil and a high sulfur fuel oil or sulfur containing oil product.

In some embodiments, the method 200 may start 201 and one or more gas and/or liquid oxidizing materials may be mixed with sulfur containing oil to produce a first mixture in step 202. In preferred embodiments, one or more of: ambient air, ozone, compressed air, oxygen, nitrogen oxygen mixtures, hydrogen peroxide, peracetic acid, acetic acid, and any other material capable of oxidizing sulfur may comprise the oxidizing material(s) mixed with sulfur containing oil to produce a first mixture.

In some embodiments of step 202, various sulfur containing oils such as Used Motor Oil, Crude Oil, Diesel, High Sulfur Fuel Oil, Mid Sulfur Fuel Oil, Off-Spec Fuel Oil, or Off-Spec Diesel may be communicated from holding tank(s) of one or more sulfur containing oil sources 11 to a heat exchanger type heater 15 to increase the oil temperature to approximately 200 degrees Fahrenheit to improve flow and processing. If the oils already have an appropriate viscosity the oil may bypass the heating stage. The oils may then flow through one or more filters 16, such as a screen-filter system and/or a horizontal centrifuge to reduce solids, and then the filtered oil may pass through a main pump 17. When the oil exits the pump 17, one or more gas and/or liquid oxidizing materials, preferably compressed gases, may be introduced to the oil stream as it passes through conduit 40 having piping size adjusted to accommodate the added volumes. The materials and oil mix (first mixture) may then pass through a static mixer type of materials oil mixer 21 to ensure proper materials to liquid dispersion.

In step 203, the first mixture may be subjected to heat (above ambient temperature) and/or pressure (above ambient pressure) to oxidize the sulfur in the first mixture. In some embodiments, the first mixture may be subjected to heat by being heated to between approximately 200 to 300 degrees Fahrenheit, and/or the first mixture may be subjected to pressure above ambient pressure and between 10 to 80 psig back pressure. In further embodiments, the first mixture may be subjected to oxidization of sulfur, optionally in a cavitation reactor 22, 22A, 22B, in the presence of a catalyst, and more preferably a zeolite catalyst, such as Zn-ZSM, Mo-ZSM, Fe-ZSM, or Co-ZSM.

In some embodiments, the first mixture may be subjected to heat and/or pressure to oxidize the sulfur via one or more cavitation reactors 22, 22A, 22B, which may receive the oxidizing material(s) and oil mixture and which may subject the materials and oil mixture to controlled cavitation. In preferred embodiments, two or more cavitation reactors 22A, 22B, which may be operated in series, parallel, or any other combination may be used to subject the first mixture to hydrodynamic cavitation. Preferably, the one or more cavitation reactors 22A, 22B, may operate between approximately 10 to 80 psi, or approximately 2 to 40 psi inlet pressure and 5-30 psi back pressure. In other embodiments, the one or more cavitation reactors 22A, 22B, may operate at any other suitable pressure so as to enable controlled cavitation of the materials and oil mixture is achieved in the cavitation reactors 22A, 22B. Controlled cavitation of the materials and oil mixture achieved in the cavitation reactors 22A, 22B, attaches oxygen to the sulfur in the oil molecules that contain sulfur. As step 204 creates heating of the oil mixture, a heat exchanger type of cooling device 23 may be used to cool the oil mixture. Preferably, the oil mixture may flow from the cavitation reactor(s) 22A, 22B, into a heat exchanger type of cooling device 23 to reduce the temperature to near ambient.

In step 204, at least one solvent may be mixed with the first mixture to produce a second mixture. In some embodiments, a stream, or other delivery method, of one or more polar solvents, such as tamisolve, N-ethyl pyrrolidone (NEP), diethyl carbonate, ethylene carbonate dimethyl carbonate, cyrene, Dimethylformamide (DMF), N-Methyl-2-pyrrolidone (NMP), propylene carbonate, may be introduced into the first oil mixture at a rate between approximately 10% to 100% of oil volume, depending on the type of oil being processed and the type of polar solvent to produce the second mixture. In preferred embodiments, the solvent may be held in a refrigerated tank solvent source 24 and may be introduced to the oil mixture stream between approximately 32 to 50 degrees Fahrenheit to lower the viscosity of the solvent and increase the density. In further preferred embodiments, the at least one solvent may be mixed with the first mixture to produce a second mixture via a static mixer. In further preferred embodiments, once the polar solvent is introduced to the oil mixture, the mixture may be passed through a solvent oil mixer 25 that may comprise a gentle static mixer.

In step 205, the second mixture may be separated to produce a low sulfur oil product and a third mixture, the third mixture having a high sulfur oxidized oil and polar solvent. In some embodiments, the second mixture may be separated by communicating the second mixture into a centrifuge 26, such as a disk stack centrifuge, for separation of the polar solvent containing oil with sulfur and oxygen (third mixture) from the oil that substantially does not contain sulfur and attached oxygen (relatively low sulfur oil product). After separation occurs there will be two streams. The first is the finished product of low sulfur oil product or very low sulfur fuel oil (VLSFO) which may be placed into a finished product tank 27. The second stream may comprise a third oil mixture which may comprise polar solvent with high sulfur oxidized oil.

In some embodiments, after step 205 the method 200 may finish 208. In further embodiments, after step 205 the method 200 may proceed to step 206 or to step 207.

In optional step 206, the one or more solvents may be separated from the third mixture to produce a high sulfur oxidized oil product, preferably via distillation or any other suitable separation method. In some embodiments, the second stream of step 205 may be transferred to a solvent distillation system type of solvent separator 28 for separation of the polar solvent and oil containing sulfur. In preferred embodiments, the solvent(s) separated from the third mixture in step 206 may be reused as the one or more solvents used perform step 204 of mixing at least one solvent with the first mixture to produce a second mixture. The solvent separator 28 may or may not be operated as a vacuum distillation system depending on the polar solvent. The sulfur containing oil separated from the polar solvent may be another product sold as a high sulfur fuel oil (HSFO) or sulfur containing oil.

In some embodiments, after step 206 the method 200 may finish 208. In further embodiments, after step 206 the method 200 may proceed to step 207.

In optional step 207, the low sulfur oil product produced in step 205 may be passed through a polar zeolite to extract additional oil holding sulfur. Zeolites are crystalline solids structures made of silicon, aluminum and oxygen that form a framework with cavities and channels inside where cations, water and/or small molecules may reside. They are often also referred to as molecular sieves. Many of them occur naturally as minerals, and are extensively mined in many parts of the world finding applications in industry and medicine. However, most of zeolites have been made synthetically some of them made for commercial use while others created by scientists to study their chemistry. At present, there are over 190 unique zeolite frameworks identified, and over 40 naturally occurring zeolite frameworks are known. In some embodiments, the low sulfur oil may be passed through a polar zeolite in the presence of oxygen. In further embodiments, the low sulfur oil may be passed through a polar zeolite in the absence of oxygen.

In some embodiments, after step 207 the method 200 may finish 208. In further embodiments, after step 207 the method 200 may proceed to step 206.

Although the present invention has been illustrated and described herein with reference to preferred embodiments and specific examples thereof, it will be readily apparent to those of ordinary skill in the art that other embodiments and examples may perform similar functions and/or achieve like results. All such equivalent embodiments and examples are within the spirit and scope of the present invention, are contemplated thereby, and are intended to be covered by the following claims. 

What is claimed is:
 1. An oil desulfurization method, the method comprising the steps of: mixing an oxidizing material with sulfur containing oil to produce a first mixture; subjecting the first mixture to at least one of heat and pressure to oxidize the sulfur in the first mixture; mixing at least one solvent with the first mixture to produce a second mixture; and separating the second mixture to produce a low sulfur oil product and a third mixture, the third mixture having a high sulfur oxidized oil and the at least one solvent.
 2. The method of claim 1, wherein the oxidizing material mixed with sulfur containing oil to produce a first mixture includes at least one of: ambient air, ozone, compressed air, oxygen, nitrogen oxygen mixtures, hydrogen peroxide, peracetic acid, and acetic acid.
 3. The method of claim 1, wherein the first mixture is subjected to oxidation of sulfur in the presence of a catalyst.
 4. The method of claim 3, wherein catalyst includes at least one of: Zn-ZSM, Mo-ZSM, Fe-ZSM, and Co-ZSM.
 5. The method of claim 1, further comprising the step of passing the low sulfur oil product through a polar zeolite to extract additional oil holding sulfur.
 6. The method of claim 5, wherein the low sulfur oil is passed through the polar zeolite in the presence of oxygen.
 7. The method of claim 5, wherein the low sulfur oil is passed through the polar zeolite in the absence of oxygen.
 8. The method of claim 1, further comprising the step of separating the at least one solvent from the third mixture to produce a high sulfur oxidized oil product.
 9. The method of claim 8, wherein the at least one solvent is separated from the third mixture using distillation.
 10. The method of claim 9, wherein the at least one solvent is separated from the third mixture is reused as the at least one solvent used perform the step of mixing at least one solvent with the first mixture to produce a second mixture.
 11. The method of claim 1, wherein the at least one solvent comprises a polar solvent.
 12. The method of claim 1, wherein the at least one solvent comprises at least one polar solvent selected from: tamisolve, N-ethyl pyrrolidone (NEP), diethyl carbonate, ethylene carbonate dimethyl carbonate, cyrene, Dimethylformamide (DMF), N-Methyl-2-pyrrolidone (NMP), and propylene carbonate.
 13. The method of claim 1, wherein the at least one solvent comprises
 14. The method of claim 1, wherein the at least one solvent is introduced to the first mixture at a rate between 10% to 100% of oil volume.
 15. The method of claim 1, wherein the at least one solvent is introduced to the first mixture at a temperature of between 32 and 90 degrees Fahrenheit.
 16. The method of claim 1, wherein the second mixture is separated via a centrifuge.
 17. The method of claim 1, wherein the first mixture is subjected to pressure above ambient pressure and between 5 to 30 pounds per square in gauge (psig) back pressure.
 18. The method of claim 1, wherein the at least one solvent is mixed with the first mixture to produce a second mixture via a static mixer. 